SAO PAULO/RIO DE JANEIRO, Oct 9 (Reuters) - Brazilian telecom Grupo Oi SA will not undo its merger with Portugal Telecom SGPS SA, but it could sell Portuguese assets acquired in the deal, acting Chief Executive Officer Bayard Gontijo said in an interview on Thursday.

Gontijo, who took over when Zeinal Bava resigned on Tuesday, said in order to pay down mounting debts the company was looking to sell non-core assets, including cell towers, real estate and its Africatel unit, which is valued at around 4 billion reais ($1.7 billion).

Altice, a holding company backed by billionaire cable entrepreneur Patrick Drahi, is looking to enter exclusive talks with Oi to buy its Portuguese telecoms operation, sources told Reuters on Thursday.

While Oi is counting on asset sales to generate cash at the moment, CEO Gontijo said he is focused on turning around the company's weak earnings in the short term, a task he said would be helped by a merger among rival telecoms.

Oi shares climbed to two-month highs in recent weeks on hopes that the company could pull off a merger with dealmaker Bava at the helm. The stock has plunged since Bava's resignation, including a 13 percent drop on Thursday.

Gontijo reiterated Oi's commitment to listing on the Novo Mercado section of the Sao Paulo stock exchange, which requires higher standards of public governance, by March 2015.